Frustration and the lack of control over it could be the single most draining aspect of the short sale process. It is a difficult thing to control but it is a powerful tool in becoming the dominant agent in your area. The challenges that are put forth, which cause so much of the frustration, are learning experiences that you can use in future transactions. It will also set you apart during your consultations with the homeowner that is looking for help. It is an indictment of the expertise your enjoy.
Look towards the unexplained and try to find a solution that will take the contract to closing. Don't succumb to the power of frustration but instead try to harness the uncertainty and find new ways to navigate those challenges. It will make you stronger and your business wildly successful.